Refrigerating apparatus



' Nov. 29, 1938. PH|L|PP 2,138,611

REFRI GERATI NG APPARATU 5 Filed Sept. 1, 1934 .1- "JJ INVENTOR. Lawns/1a 9. P/f/L/PP a ATTORNEY. 7

Patented Nov. 29, 1938 UNITED STATES PATENT OFFICE mesne assignments, to Nash-Kelvinator Corporation, Detroit, Mich., a corporation of Mary land Application September 1, 1934, Serial No. 742,419

8 Claims.

My invention pertains to refrigerating systems and more particularly to an automatic humidity responsive-control for regulating in accordance with humidity conditions.

It is an object of my invention to provide a low temperature humidostat comprising a wet bulb and a dry bulb enclosing separated quantities of a volatile refrigerant and means responsive to the pressure differential to control suitable regulating means for automatically maintaining the optimum conditions for the preservation of articles and substances stored therein.

It is a further object of myinvention to provide a humidostatically regulated refrigerating system comprising a wet bulb and a dry bulb and means for continuously wetting the wet bulb of the humidostat by the drop from the cooling unit.

It is also an object of my invention to provide a low temperature humidostat comprising pressure actuated means responsive to humidity and adjustable means whereby its operation may be accurately set to regulate an associated refrigerating system.

The invention itself, however, both as to its organization and its operation together with additional objects and advantages thereof, will best be understood from the following description of specific embodiments, when read in conjunction with the accompanying drawing, in which:

Figure 1 is a diagrammatic view schematically representing a refrigerating system comprising a humidostatic control arranged in accordance with my invention.

Figure 2 is a front elevational view showing another embodiment of a humidostat device suitable forcontrolling the refrigerating system;

Figure 3 is a side elevational view; and

Figure 4 is a rear elevational view thereof.

Referring more particularly to Fig. I of the drawing, the apparatus therein represented comprises a cooling unit II which isdisposed within a compartment to be refrigerated, as represented by the dotted lines l2, and which is supplied with refrigerating medium from a remotely disposed source I3 to which it is operatively connected by suitable conduit means. The cooling unit ll may be of any well known type, as specifically disclosed, it comprises an evaporator which is supplied with volatile liquid refrigerant from a source comprising a compressor condenser unit. As the vaporized refrigerant is withdrawn from the cooling unit ll through the suction line IE it is compressed in the compressor l6 and passes under high pressure through the condenser coils I! where its'latent heat of vaporization is dissiin the refrigerating compartment, as will be subsequently set forth.

Disposed within the refrigerating compartment ,1 have provided a humidity responsive device or humidostat 3|, which is especially suitable for accurate operation at the low temperature conditions to'which it is exposed. For this purpose, I have devised a special humidostat which comprises a relatively large vessel or dry bulb 32 into which a conduit member 33 is hermetically sealed with its open end directed toward the bottom of the bulb 32. The conduit member 33 rises from the bulb in inverted U formation having its other downwardly directed branch closed to provide a receptacle or bulb 34, on the end thereof, which may be designated as the Wet bulb, because associated means is provided for continuously wetting the same, in a manner to be subsequently set forth.

A quantity of dense electrically, conductive liquid 35, such as mercury for example, is provided in the dry bulb 32 which is sufiicient to.

partially fill the space therein leaving a free space for evaporation of a relatively light volatile liquid 36 which is also-provided therein and reposes on the surface of the dense liquid 35. I have found that the low pressure volatile refrigerants, such as ethyl chloride for example, are 'especially satisfactory forthis purpose. A quantity of the volatile liquid 36 is alsoprovided in the wet bulb 34 on the closed end of the conduit member 33 which is preferably made of glass or other electrical insulating material.

A second conduit member 4| is provided hava ing its open end sealed into thedry bulb vessel 32 below the level of the dense liquid 35 therein, and it is of inverted U formationwith its outwardly projected end hermetically sealed to a resilient pressure varying device comprising a flexible metal bellows 42. the flexible bellows 42 I have provided an adjustable screw 43 which is threadably supported in a stationary bracket 44 in abutting engagement with the end of the bellows. A knurled knob 45 may be provided on the end of the threaded screw 43 to facilitate adjusting the same. A compression spring 46 is preferably disposed within To adjustably distort the flexible bellows 42 to extend the same when I the adjusting screw 43 is withdrawn from the bottom of the bellows.

The second conduit member 4| and its connected bellows are filled with the dense liquid 35 which is provided in the large vessel or dry bulb into which the open end of the conduit is sealed. By turning the knurled knob 45 to compress or extend the metal bellows 42 the level of the dense liquid 35 within the dry bulb 32 may be varied to adjust the pressure therein and hence vary the height of the column of dense liquid 35 within the first conduit member 33. The quantities of volatile liquid 36 disposed in the dry bulb and in the wet bulb are separated by the mercury which surrounds and seals the lower end of the first conduit member 33.

Different pressures are set up byvaporization of the liquid in the wet bulb and in the dry bulb in accordance with the temperatures to which the bulbs are exposed, and the dense liquid is forced up the first conduit member 33 a certain distance in accordance with the pressure difference to which it is exposed at opposite ends of the conduit.

By continuously wetting the bulb 34 on the closed end of the first conduit member temperature difierences are established which vary in accordance with the humidity of the atmosphere or gases to which the. bulbs are exposed in the refrigerated compartment. The vapor pressure differences set up by vaporization of the separated quantities of the volatile liquid are thus caused to Vary according to the humidity variations.

For continuously wetting the bulb 34 on the end of the conduit member a wick 5| is provided which surrounds the, bulb and extends into a water dish 52. The water dish is continuously supplied with water by catching the drip water which is caused by the moisture condensing upon the cooling unit, and for this purpose a catch basin 54 is mounted under. a drain 55 provided in the drip apron .56 under the cooling unit I l. The catch basin 54-" is spaced from the water dish 52 and it is connected thereto through an elongated pipe 51. The upper edge of the catch basin 54 is substantially lower than the upper edge of the water I dish 52 and the excess drip water which falls into basin ovrflows the edges at the basin and passes into the regular drip pan or a suitable overflow. The water dish 52 thus receives only a sufilcient quantity-of water to supplythe evaporation from the wick 5|, and the temperature of the drip 'water cannot directly 'effect the temperature of the wet bulb 34 and cause an inaccurate operation of the humidostat.

In operation the height of the liquid column in the closed conduit member 33 varies ina'ccordvance with the temperature difference of the two bulbs. Since the bulbs are enclosed'in the same compartment their temperatures vary only in accordance with the rate of evaporationf-of water from the wick which is in accordance with. the

therein I provide an electric contact member 6| I which is mounted in electrically insulated relation in the walls of the conduit 33 for conductive enagement by the liquid when it rises to a predetermined level therein. A second electric contact member 32 extends into the large dry bulb vessel v 32 in continuous conductive engagement with the dense electrically conductive liquid 35 therein.

When the liquid engages the insulated contact member 6|, an energizing circuit is completed from any suitable source of current 64 through 5 the conductive liquid 35 and from the other coni tact member 52 returning through a conductor 68 to the source of current 64.

When the relay winding R is energized it pulls up its armature, opens its back contacts 25, which are connected into the motor energizing conductor 24, and stops the motor compressor set. Themotor compressoris thus intermittently operated in accordance with the humidity in the refrigerated compartment. It will be readily understood that the relay may be arranged with front contacts to start the motor when it pulls up instead of stopping it. The relay may be utilized to accomplish various other controls, as desired, and may also control an electromagnetic valve II on a water spray or humidifier 12 by providing suitable conductors 13 and 14 for connecting it in circuit relation with the motor either one or both of which may be simultaneously controlled by the relay R. If applied to a multiple evaporator system or a system of a different type,

- my humidostat may be appliedto control an appropriate element thereof as by regulating the admission of cooling medium to the cooling. unit or in any other suitable manner as will be readily understood by those skilled in the art.

In operation the humidity within a. refrigerated compartment increases as the temperature rises, and decreases as the temperature is lowered, hence when the compressor unit has been in operation for a long period of time the humidity within the compartment will be lowered. Under this condition the liquid column falls to a low level in the conduit 33 and opens the relay circuit which operation may in turn be utilized to open the motor circuit. The intermittent control of the compressor is thus accomplished in response to the humidity conditions and the varyprovided by bending a glass tubular member 8| ends 82 and 83 adjacent the open portion of the loop turned back to follow the curvature of the tube to provide receptacles in which a volatile liquid will repose. The receptacle portions 82 in the form of an open circular loop having its and 83 on the ends of the tube may be enlarged to provide greater volumetric space if desired and they correspond functionally to the wet bulb and the dry bulb portions of the previous embodiment.

The curved tubular member 8| is supported by a bar 86 which is pivoted upon a stationary bracket 81 rising from a suitable base plate 88. The pivotal mounting preferably has sufficient friction to maintain any adjusted position and it on the stationary bracket 81. A dense electrically conductive liquid 35, such as mercury, is ,Y provided in the loop portion of the conduit. An

70- is provided with an indicating pointer 90 which. is disposed to move adjacent a scale 9| mounted electric contact 84 is inserted through a mercury well in a wall of the curved tube 8| adjacent one end of the loop, and a second electric contact 95 is inserted into the middle portion of the tube 8| whereby an electrical circuit connection may be completed through the mercury 35 when it bridges both of the contact members. A inercury reservoir 96 may also be provided adjacent the electric contact comprising a bulb which is 10 adapted to receive or discharge a quantity of mercury into the curved tube 8|.

In operation the pressure difference set up by separated quantities of volatile liquid 36 which are disposed in the bulbs 82 and 83 at opposite ends of the tubular member 8| force the mercury column around the loop to a balanced position. By providing 'an adjacent water dish 52 and a suitable wick 5| for continuously wetting one of the bulbs, the device is made to operate in accord- .2o.ance with the humidity to which it is exposed.

The degree of humidity which will causethe' mercury to complete the circuit between the electric contact members 94 and 95 is readily adjusted by rotating the tubular loop 8| upon its pivoted sup- 5 port and thereby balancing the height of the mercury column against the pressure set up bythe vaporizing fluid. By referring to the associated pointer and scale as the tubular member is rotated the device may be readily set for the de- 30 sired operating characteristics.

It will be seen that I have provided a refrig-' erating system comprising an accurate, simple, conveniently adjustable, low temperature humidostat for automatically regulating the system or associated elements to maintain the optimum conditions for the preservation of organic material stored within a refrigerated compartment.

Aside from the specific embodiments of the invention herein shown and described, it will be understood that numerous details of the construction may be altered or omitted without departing from the spirit and scope of the invention as disclosed and claimed, and that I do not desire to limit the invention to the exact constructions herein set forth.

I claim as my invention: 7

1. In combination in a refrigerating system a cooling unit for cooling a gas and adapted to condense moisture from the gas, means for supplying a cooling medium thereto, and humidity responsive means for regulating the operation of said first means in accordance with the relative humidity condition of the gas being conditioned by the cooling unit, said humidity responsive 55 means comprising a wet bulb and a dry bulb and means for continuously applying the condensation drip from the cooling unit to the web bulb.

2. In combination in a refrigerating system a cooling unit, a first bulb, a small quantity of vola- 60 tile liquid therein, a second bulb, a small quantity of a volatile, liquid and a quantity of mercury in said second bulb, conduit means interconnecting said first bulb with said second bulb below the level of the mercury therein, means for wetting 3 one of said bulbs to maintain a temperature differential relative to the other bulb according to the humidity of the atmosphere adjacent said cooling unit and means responsive to the level of mercury in said conduit for regulating the supply of cooling medium admitted to said cooling unit.

3. In combination in a refrigerating system a 6 cooling unit, means for supplying cooling medium to said unit, humidity responsive regulating means disposed adjacent said cooling unit comprising a pair of interconnected bulbs, a quantity of volatile liquid in each of said bulbs, means for 10 continuously applying the drip from the cooling unit to wet one of said bulbs independently of the temperature of the drip, and means responsive to the pressure differential between said bulbs for controlling said first named means. 16

4. In combination in a refrigerating system, a cooling unit, means for supplying cooling medium to said unit, humidity responsive regulating means disposed adjacent said cooling unit comprising a wet bulb and a dry bulb, means for continuously 20 wetting said wet bulb from the cooling unit drip water independently of the temperature thereof comprising a wick, a catch basin, a' wick watering dish having its upper peripheral edge disposed at a higher level than the upper edge of the catch asin, conduit means interconnected between said catch basin and said wick watering dish, and means responsive to the pressure differential between said bulbs for controlling said first named means.

5. In combination in a refrigerating system, a cooling unit, a device exposed in the space cooled by said unit and responsive to the relative humidity of the gas in said space, a humidifier for humidifying said space, means for controlling the circulation of a cooling medium in said unit, and means actuated by said device for controlling said humidifier; and said first mentioned means to maintain optimum conditions for the preservation of organic matter in the. cooled space.

6. Air treating apparatus comprising, a cabinet, a refrigerant evaporating element for cooling circulating air in said cabinet and for extracting moisture from said air, a thermostatic element including a wet bulb and conduit means associated '45 with said evaporating element and said wet bulb for conducting extracted moisture from said evaporating element to said wet bulb.

7. Air treating apparatus comprising, a cabinet, a refrigerant evaporating element for cooling circulating air and adapted to extract moisture from said air, a thermostatic element for controllin the operation of said evaporating element, said thermostatic element including a wet bulb and means associated with said evaporating element 5 and said wet bulb for conducting extracted moisture dripping from the evaporating element to said wet bulb.

8. Air treating apparatus comprising, a cabinet, a refrigerant evaporating element for cooling ciro culating air and adapted to extract moisture from said air, a thermostatic element for controlling humidity conditions, thermostatic element including a wet bulb, and means for conducting extracted moisture to said wet bulb.

LAWRENCE A. PI-IILIPP. 

